ipaccess: fix segfault if bsc port already in used

This patch fixes a segfault if we try to bind to an already
busy port, it can be easily reproduced with:

$ test/./e1inp_ipa_bsc_test &
<0003> ipaccess.c:830 enabling ipaccess BSC mode
<0000> e1inp_ipa_bsc_test.c:241 entering main loop
$ test/./e1inp_ipa_bsc_test
segfault
1 file changed